Can These Machines Power My House?

Yes, if you can generate the required power. The magic number for powering an off-grid house is 300 watts of continuous power. This is the average power consumed. When stored in batteries, this is enough power for lights, fridge, freezer, washing machine and well pump. This would be for a family of four. This is 300 x 24 or 7200 watt hours per day or 7.2 kilowatt hours (kWh). If the house in question is on grid (mains) power, then the usage is typically three or four times the consumption of the off grid people.Back To Top

Can I use the power directly from the hydro generator?

Yes and no, but mostly no. Our generators first produce alternating current that is three phase, three wire power that will be at a frequency much higher than the usual 50 or 60 Hertz. This is converted to DC power using a rectifier which is usually located at the generator.

If the system output is feeding the grid, batteries are not necessary as power not used by the household is sent to the grid and counts against your consumption.Back To Top

Why are the generators tunable and what does that mean?

This means that our machines can be “tuned” so that the output of the generator can be matched to the output of the turbine wheel. At any site, the turbine will generate the most power when operated at the best speed. Our machines (with the exception of the Watter Buddy) have magnet rotors that can be raised and lowered which increases or decreases the magnetic flux. This makes the machine go faster or slower so the best speed can be achieved which is where the highest power is generated. There are electronic devices that can do this. They are called Maximum Power Point Trackers or MPPT’s. These are not required with our machines so there is not only a savings in cost, but these are electronic devices and would be the weakest link in your system. The tuning adjustment would be made when first setting up the machine and then fine tuned at a later date if the flow rate changed.Back To Top

Do I have to use batteries?

If you have a system that is feeding the grid, then batteries are not required as you can feed your hydro power into a grid tied inverter. This usually means that when the grid is down, you cannot power up anything in your house. There are now some inverters that allow for some output as long as this does not exceed what is being generated. Since there are battery based inverters that can operate on or off grid, systems are often installed that use these so that there will be power for the household when the grid is down.

The beauty of a battery based system is that only the average load needs to be generated. In this way, power is stored when not needed and can be used at much higher levels when required. The only way around this is with what is called an AC direct system. This system generates AC power right from the turbine/generator and that powers all the loads. This means that the peak load must always be generated so when a motor like the one in your well pump starts, there is enough power to start it—or the system will collapse. This usually means that the generator has to make a minimum of about three kW. This all means that if you compare this to a battery system, the AC Direct one will need a much larger turbine/generator and pipeline and also consume much more water.Back To Top

How long will batteries last?

Usually lead-acid batteries are used in these systems. These can be what are called flooded types that have removable caps that allow you to add water if needed. Then there are sealed types that require no maintenance. There are also several other battery types, but at this time, they all cost more than the lead based ones.

Battery life depends on many things. However, the batteries in a hydro system last longer than with other system types (wind, solar) as they do not sit for long in a discharged condition. This is the usual cause of shorter life. Many customers report the lifetime of their batteries exceeding ten years.Back To Top

What keeps my batteries from overcharging?

In a battery based system, there will be times when the batteries become fully charged and no more energy should be added to them. A charge controller is used that monitors the battery voltage as this is a good indicator of charge level. When the voltage reaches a certain level, power is diverted to a secondary load such as an air or water heater. A solar type control regime cannot be used, since with solar, the panels are disconnected from the batteries when fully charged. This cannot be done with hydro as the voltage would go quite high and fry your controller.Back To Top

What is equalizing and do I need to do it?

Lead acid batteries benefit from a controlled overcharge called equalization. This means that the battery voltage is allowed to rise above the normal range—typically once a month. This causes all the cells to reach a full charge and have equal voltages. The increased gassing that accompanies equalization also stirs up the electrolyte so it does not stratify into layers of different densities. Sealed batteries can also be equalized, but the voltage can only be permitted to rise slightly or else these batteries will pop their safety vents.Back To Top

What battery voltage should I use?

In the beginning, most systems were 12 volts. The systems were smaller in the past and inverters were not reliable, so often loads were operated directly from the batteries as there were many appliances available that operated on 12 volts to cater to the RV market.

Now most systems operate everything from inverter output and use standard appliances. Today’s inverters are both powerful and reliable. Only the smallest systems use 12 volts these days. As the system power level increases, so should the battery voltage. Higher voltage means lower current for the same power and enables the use of smaller cabling and breakers.Back To Top

How far can I transmit this power?

We have customers that transmit power over a mile. What we usually do for this is use a generator that produces a higher voltage such as 120 or 240. This is sent using three wires (it is three phase power) to a transformer panel at the batteries. This steps down the power to battery voltage and then a rectifier converts the AC power to DC. Using transformers is an economic decision as it may be cheaper to use larger wire and transmit the power at battery voltage. This is also simpler than transformers.Back To Top

Should I put the batteries and inverter in the powerhouse with the turbine?

The short answer is no. There are several reasons for this. One good reason to have batteries and inverter in or near the point of use is so you can look after them. The batteries will need maintenance if they are flooded types. Both the batteries and the inverter would like to be warm and dry.

A better reason to put whatever you can closer to the point of use has to do with current levels. I have heard many people ask me if the inverter should be at the batteries since it produces higher voltage (than the generator) and that should be easier to transmit. The problem arises when the inverter needs to start a motor or some such. A half horsepower motor like those in well pumps might require a surge of several kilowatts to start. With the inverter at some distance from your house, you might find that you need larger transmission lines than you would to transmit the generator power—even if it is at a lower voltage.Back To Top

How long will these machines last?

This is a big variable. Some of the first machines made here are still operating after 30 years. While the machines can last a long time, they can also be damaged from lack of maintenance and poor operating conditions. Since the machines operate next to water, the humidity is often 100% where they are. This can cause corrosion in both the wiring in the junction box or in the bearings. It would be good preventive maintenance to check both of these at least once a year.Back To Top

What about freezing?

The colder it can be where your machine is, the more critical it becomes. The best way to keep things like your pipeline from freezing is to bury it. This is also the best way to protect it and stabilize it even if it does not freeze where you are. This is not always possible of course. Exposed sections can be covered with hay, leaves, straw, sawdust or outdoor pipe insulation. If the water is running, even a shallow burial will help—if the water is kept running when cold. Polyethylene pipe is more flexible than PVC and this makes it much less prone to damage from freezing. When PVC freezes, the damage can be total.Back To Top

How do I get the water into the pipe? Do I need to build a dam?

Usually you don’t have to do much to arrange for the water to enter your pipeline. There are two basic ways to build an intake. The water can be taken from a pool in the creek if it is deep enough to install a screened box at the beginning of the pipeline. Then it can usually be arranged for the pipeline to run downhill from there and the water can flow downhill through the length of the pipeline. The other possibility is to install a wedge wire screen at the beginning of the pipeline and arrange for the water to flow over it. This makes for a self-cleaning intake as the water flowing over the screen will wash away the debris and only very small particles can make it through.Back To Top

Does the pipeline have to run downhill the whole length?

No, but it would be best if it did. It would also help if the slope did not change over the length of the pipe. If the pipe can run downhill for a bit at the beginning, it will make it much easier to start the water flowing as a valve can be installed at the low point and opened to start the flow. A pipeline can also run uphill for a bit and this may require adding a small valve to vent the line if it traps air. Automatic valves are available for this. Some pipeline will require venting to start the flow and small holes can be drilled in the pipe to allow for air to escape. These can be plugged with small screws after the air is purged. If the pipeline is buried, either the automatic valves can be used or a small valve can be installed and a vertical length of pipe installed so that you can reach in with a long handle to operate this valve and release the air.Back To Top

Can a siphon be used?

Yes, siphons are used on a regular basis. This is usually done at the beginning of a pipe where it has to rise out of the creek and go over a bank or this can be used to go over a dam when it would be difficult to alter the dam. These can be difficult to get started. A valve can be added to the high point of the line and this can be used to fill the line with water. Then the stop valve is opened at the turbine and the flow that starts should suck along any trapped air. Another way to start the line is to suck the air out with a hand or motor operated vacuum pump that pulls water into the line. Air may tend to accumulate in the high spot of a siphon system. If the velocity of the water is not high enough to pull the air along, air may accumulate and stop the flow.Back To Top

How much noise do the machines make?

Usually not much. Often the machine(s) are installed in a small powerhouse so that they are protected from the weather and so is any other equipment mounted inside. This helps reduce noise. You may find that your machine makes more noise at certain speeds as the rotor tends to have resonant frequencies. This can be changed by altering the height of the rotor a bit which will change the speed some and reduce or eliminate noise.Back To Top

What about regulations that might apply to this?

Most places in the world have regulations that cover water use. It is best to investigate what might apply to your project. These vary from one area to another so I cannot give a good answer to this. Of course, any water your system uses is returned to the brook it came from in its original condition.Back To Top